208 datasets found

We present the analysis of 2.1 years of Fermi Large Area Telescope (LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert Telescope (BAT) survey. Only the two...

We use homogeneous samples of radio-quiet Seyfert 1 galaxies and QSOs selected from the Sloan Digital Sky Survey to investigate the connection between the velocity shift and the...

Galaxy-galaxy mergers and close interactions have long been regarded as a viable mechanism for channeling gas toward the central supermassive black holes (SMBHs) of galaxies...

Observations of H_2_O masers from circumnuclear disks in active galaxies for the Megamaser Cosmology Project (MCP) allow accurate measurement of the mass of supermassive black...

We use publicly available XMM-Newton data to systematically compare the hard X-ray photon indices, {Gamma}2-10keV, and the iron K{alpha} emission lines of narrow- and broad-line...

An analysis of archival mid-infrared (mid-IR) spectra of Seyfert galaxies from the Spitzer Space Telescope observations is presented. We characterize the nature of the mid-IR...

We present the first results from a high sampling rate, multimonth reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from...

We present optical spectroscopy for an X-ray and optical flux-limited sample of 677 XMM-Newton selected targets covering the 2deg^2^ Cosmic Evolution Survey field, with a yield...

We report a search for H_2_O megamasers in 274 SDSS type-2 active galactic nuclei (AGNs; 0.3<z<0.83), half of which can be classified as type-2 quasi-stellar objects...

We present optical observations of the low-luminosity Seyfert 1 nucleus of NGC 4395, as part of a multiwavelength reverberation-mapping program. Observations were carried out...

We present a three-dimensional study of the local (<=100h^-1^kpc) and the large-scale (<=1h^-1^Mpc) environment of the two main types of Seyfert AGN galaxies. For this...

A reverberation-mapping program on NGC 4395, the least luminous known Seyfert 1 galaxy, undertaken with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope...

We present the results of 3 yr of ground-based observations of the Seyfert 1 galaxy NGC 5548, which, combined with previously reported data, yield optical continuum and...

We have derived the near-infrared structural components of a sample of Seyfert and starburst (SBN) host galaxies by fitting near-infrared images with a new two-dimensional...

We present UBVRcIc magnitudes of 49 comparison stars in the fields of the Seyfert galaxies Mrk 335, Mrk 79, Mrk 279, Mrk 506, 3C 382, 3C 390.3, NGC 6814, Mrk 304, Ark 564, and...

Star Formation Across Cosmic Time (SFACT) is a new narrowband (NB) survey designed to detect faint emission-line galaxies (ELGs) and QSOs over a broad range of redshifts. Here...

We present the second catalog of serendipitously discovered compact extragalactic emission-line sources-H{alpha} Dots. These objects have been discovered in searches of...

The discovery of spectral type transition of active galactic nuclei (AGNs), the so-called "changing-look" (CL) phenomenon, challenges the widely accepted AGN paradigm, not only...

Broadband photometric redshifts are routinely obtained for galaxies to estimate their distances. While effective for many uses, the common resolution in z of 0.01-0.02 is too...

We report on multi-wavelength observations of the X-ray transient Narrow Line Seyfert 1 (NLS1) galaxy WPVS007. The galaxy was monitored with Swift between 2005 October and 2013...